Montana 3.4L into a 3.1L GP???

[Steve Is Legend]

I've got a 2000 Montana with the 3400 v6, the trans went out, so I found a 1994 Gran Prix that has a seized 3100 v6. I was wondering if this swap would work... 3.1 to 3.4.

[bszopi]

Welcome! Yes, you can easily swap the 3400 into the Grand Prix. Check out www.3x00swap.com and go to the downloads area. You will find a 3400 swap guide. Won't be exactly for your car, but it'll give you a pretty good idea on what all is involved.

[nicholz26]

thats odd..lol I just did that swap...have a problem though. I mixed up the injectors from both motors. I thought they were all the same..? Anyways I have an 02 grand prix w/ the 3.1. Swapped the 3400 in it..wont start..have spark on all six. all six injectors squirt...got decent FP. It was kinda backfiring through the intake..and then making a weird squeek kinda sound. Like the pistons were being stopped very fast..by gas or something in there? lol idk but I cannot get it going..Checked the readings on all injectors to. Lowest one was 11.5.

I really dont know what to do now if the injectors are indeed the same. I was hoping they were different adn that was my problem. but who knows. any ideas will be apprciated.

Have only worked on the 3x00s for 8 yrs...lol love my pushrods. the 3400/5spd is sitting though:-\ I miss it lol

[bszopi]

Are you sure you have the plug wires on the right spots? Do NOT use the numbering on the LIM to place the wires, as it is backwards. The numbers on the LIM that are near the radiator correspond to the rear cylinders, and the numbers on the rear of the LIM correspond to the front cylinders. Besides that, I'd just make sure all plugs are connected.